Cheerful Family has the same effect as a Blended Family, but is similar to Meme Family.
We know that mating Memetchi with Mumutchi makes Meme family, but any other Meme combination (Memetchi, Iwatchi, Onputchi, Mumutchi, Sukatchi, Uhyotchi) [without 100% if it's Memetchi/Mumutchi] combo would be a Cheerful Family.
I'm actually aiming for one this generation, though I will go for a Space Family.